C More Clearly

“The blog entry includes a graphic that is apparently the results of a poll asking people to guess the extent of agreement among climate scientists on [the question of whether humans are causing global warming], and most people way underestimate the level of agreement. I don’t know the source of those poll results; it’s not provided in the blog entry. Interpretation of those results hinges on the question people were asked.”

Image from SkepticalScience.org

John Cook (the blog author) sent me an email reporting that he’s updated his blog post to clarify this issue:

“The Consensus Gap is the difference between the public’s perception of how much agreement there is among scientists that humans are causing global warming (red distribution), compared to the actual 97% consensus among scientists publishing in the peer-reviewed literature (green line). The public perception data comes from a survey of a US representative sample conducted by John Cook (ongoing research), answering the question “How many climate experts agree that the global warming we are witnessing is a direct consequence of the burning of fossil fuels by humans?” The options available were Less than 5%, Between 5% to 10%, Between 10% to 30%, Between 30% to 50%, Between 50% to 70%, Between 70% to 90%, Between 90% to 95%, More than 95%.”

So now I can address the issue head-on. The survey of the literature and author survey both address the level of scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW). The opinion poll asks “How many climate experts agree that the global warming we are witnessing is a direct consequence of the burning of fossil fuels by humans?”

I am just one scientist, so this will be a relatively small sample size. But here goes:

I believe that human activity is very likely causing most of the current global warming.

I do not believe that the global warming we are witnessing is a direct consequence of the burning of fossil fuels by humans.

To the extent that lots of other climate scientists might agree with me, there’s no inherent conflict between the 97% result (papers and scientists) and the median 50% (public perception) because they are two different questions, and both results can be right.

What’s my problem with the statement that “the global warming we are witnessing is a direct consequence of the burning of fossil fuels by humans?” Three problems, actually:

The observed increase of CO2 is only about 80% due to burning fossil fuels. Land use changes account for the other 20%.

The change in radiative forcing caused by the anthropogenic increase in Tyndall (greenhouse) gases is only about 65% attributable to CO2. The rest is associated with CH4, N2O, O3, chlorofluorocarbons, etc.

The global warming we are witnessing is the combined product of these Tyndall gas increases (and their feedbacks, along with changes in aerosol concentrations, changes in solar activity, variations in the Pacific Decadal Oscillation and other forms of natural variability, and so on.

This view is fully consistent with the latest (fourth) IPCC report, which concluded that all of man’s effects combined (1 plus 2 plus part of 3) was merely likely to have caused most of the recent warming (with the rest of it, possibly even the majority, due to the rest of the factors listed in 3). Indeed, based on climate observations since the report came out, my own opinion has increased to very likely, while points 1, 2, and 3 still stand.

Now I don’t know whether the public’s answers would change much if they were presented with a fully nuanced question that accurately reflected the IPCC consensus. I suspect that they would overestimate the extent of disagreement. But such a question was neither asked nor answered.

HS –
1. Your critique of Cook’s study would be valid if he hadn’t also carried out a separate survey of the authors. If it were just an abstract survey there would be lots of room for criticism like you have made. With the confirmation through direct contact with the authors, the results become unambiguous.
2. http://www.skepticalscience.com/human-co2-smaller-than-natural-emissions.htm
3. There are many anthropogenic sources for methane.
4. Salby is wrong.
– John

1. No, to contact only authors that have explicitly endorsed AGW to again ask them if they endorse AGW is a rigged survey that’s guaranteed to have essentially 100% agreement, and meaningless results. That is only 1 of the many other problems documented in my links above.

1. A little help please. Where did you document that they only attempted to contact authors that had explicitly endorsed AGW? It’s not in your primary blog entry on the subject.
2. Again, I don’t have time to go on a fishing expedition. First off, to be clear, nothing is “the” driver of atmospheric CO2 or global temperatures. Choose a particular paper making a particular claim and I’ll have a look at it.
3. Are cattle natural sources?
4. That a 1% change to the energy budget would not significantly affect global temperatures.

It does not mean what you think it means. What Frölicher et al concluded was that it wasn’t possible to tell whether the fraction of anthropogenic CO2 being absorbed by the land and oceans was decreasing or increasing. They estimate that it’s holding steady at about 55% of emissions, meaning 45% of what we emit is accumulating in the atmosphere. This is consistent with estimates by others as summarized by the IPCC. They also showed that volcanoes and ENSO are responsible for short-term variations on top of the long-term anthropogenic trend, which is something we also knew already, though now much more precisely thanks to their work.

So you are correct in the sense that I do not refute Frölicher et al 2013.

1. this i clearly a lie, or enormous incompetence, since the self-ratings includes several that deny AGW. If they asked only those who agree with AGW to self-rate their paper, there should be NO paper denying AGW. In fact, there were more that

Marco –
Though the top two downloaded articles from the journal are skeptical articles with serious flaws, they might be the only two such articles. The journal has a mainstream publisher, has been around a long time, and for example one of the articles in the current issue has Jonathan Overpeck as second author. Just from checking it out now I found an article that will be useful in my future research. (So thanks for asking!)
– John

It is sad to see the issue of climate change so politicized. The established science is clear and we are making very few efforts to avert catastrophic climate change. Our children and grandchildren will pay the price for our dithering and those who obscure the science to rationalize our dependence on fossil fuels risk their sustainable future. Let’s find practical alternatives to fossil fuels while there is still time to make a difference.

1. The fact is Cook claims a 97% consensus and hides the fact that he found a 0.14*.326 = <5% "consensus." How can you in good conscience gloss over this? This is only one of the problems, not to mention the biased, subjective rating process that clearly misrated papers, including those of Richard Tol commenting above.

2. "Consensus has little place in science, but how is a non-scientist to know what has been established scientifically except by consensus?" If it doesn't belong in science, it also doesn't belong in explaining science. To do so is a gross misrepresentation of the tremendous uncertainties inherent in climate science and diversity of opinions. A prime example is conflating natural climate change with AGW, as was done in the original "97%" "study" I was the first to expose in 2010:

5. As shown by Salby, temperature model projections track CO2 projections perfectly 1:1, to the exclusion of other, much more important independent variables such as water vapor and cloud, for which there is ample evidence of negative feedback. In addition, satellite and radiosonde data both demonstrate total atmospheric water vapor has decline, opposite to model assumptions. The models do, in fact, falsely assume a positive feedback from WV and cloud.

6. Here we go again – Salby discusses all of this and demonstrates via at least 4 means that anthropogenic emissions are "incompatible" with atm. CO2 levels. Watch the lecture again, if you even did once.

7. I agree the models are completely unreliable. Any sane person would agree:

I don't have any "preference" for what the data says. My post linked above simply shows the inconvenient graph demonstrating the disconnect between anthropogenic emissions and atmospheric levels of CO2, no models required.

8. As to the alleged refutations of Humlum et al, see my post on Humlum's paper and read Humlum's reply in the comments.

1. Once I decide a paper is irrelevant, methodological issues do not concern me.
2. You didn’t answer my question.
3. Perhaps part of our disagreement is that we live in alternative universes. I went to your link, typed in “All of the increases” in the search window, and came up blank. I did find a hit, though, with “All of these increases…” The word “these” refers back to the previous sentence, which says “Significant increases in all of these gases have occurred in the industrial era.” I agree with the IPCC that all of the significant increases are attributable to human activities. The natural change (for CO2) I estimated as only about 4% of the total change. So it seems I’m part of the consensus again.
4. My statement includes Salby.
5. Sorry, you’re not entitled to your own facts.
6. I saw Salby’s lecture in person in Melbourne, and it was entertaining in a “spot the flaw in the logic” sort of way. I’ve no desire to play the game again.
7&8. My earlier comment stands. Humlum has been demonstrated to be logically incorrect.

1. I said it was irrelevant three weeks ago: http://blog.chron.com/climateabyss/2013/05/the-size-of-the-c/ How convenient that I have the evidence on my side.
2. My question was: “How is a non-scientist to know what has been established scientifically except by consensus?” Your answer was: Not by consensus. I feel smarter already.
3. You changed the direct quote from “these” to “the” first and thereby altered the meaning. I just changed it back. I even kept “all”. Neener neener.
4. A text search on the word “assume” in S Bony et al. shows that the word appears only in the Appendix, and only in the context of defining the meaning of “feedback”. A text search on the word “adopt” shows zero hits. Instead, the paper talks about such things as “feedbacks produced by climate models”. As I said earlier, feedbacks are emergent properties, not assumptions.

I agree that this is no longer useful. You’ve been willing to dialogue until now, so maybe when you are thinking clearly you’ll be able to re-read Bony et al and realize that feedbacks are an output parameter of climate models, not an input parameter. Once you’ve made at least that much progress, come back again and we can try some more.

1. Cook & Co. looked at almost 12,000 abstracts [using a biased selection process documented in links I provided]. Of the 12,000 abstracts, only 32.6% expressed an opinion on AGW. They then contacted authors of the 32.6%/~4,000 abstracts that expressed an opinion on AGW, and got only a 14% response rate. Of the 14% of authors from 32.6% of 12,000 abstracts they then claim a 97% “consensus.” Duh. How can such a statistical travesty and rigged survey be considered science?

2. Regardless, “consensus” has no place in science. Ask Einstein, who said only one fact was necessary to disprove relativity.

3. You say “nothing is “the” driver of atmospheric CO2″

So, I take it you disagree with the statement in the IPCC AR4 that “All of the increases [in CO2 concentrations since pre-industrial times] are caused by human activity” right?

4. Doesn’t matter. As shown in Salby’s talk, methane emissions have declined over the past couple decades even though man-made emissions, including cattle, have increased. Why do you suppose that is?

5. Salby’s point, if you watch the lecture, is that climate models track CO2 projections 1:1 to the exclusion of all other independent variables, including water vapor and clouds. All climate models assume positive water vapor feedback, which has been disproven by observations. All models assume positive cloud feedback, also disproven by observations. To assume a 1% “increase in energy” from CO2 without any compensating negative feedback is a modelling fantasy. The tropical tropospheric “hot spot” predicted by models would require an impossible decrease in entropy without work input.

6. I’m well aware what Frolicher et al says and have a copy of the paper. It is clear from the paper that they have inadvertently shown that atm. CO2 doesn’t track man-made emissions. Although they are unwilling to even consider the hypothesis that man-made emissions are unrelated to atmospheric CO2, Salby and several others I linked to do it for them.

1. You no longer claim that they only contacted authors who explicitly endorsed AGW. Good. That is what I had questioned from your previous comment. I, in turn, did not claim that their survey was “science”.
2. Consensus has little place in science, but how is a non-scientist to know what has been established scientifically except by consensus?
3. I have not yet found your exact quote in the SPM or the WG1 reports…what page is it on? If the quote is accurate, I do disagree with it. In my judgment, natural forcing (solar, volcanic) would have caused something like an 0.2 C temperature rise since preindustrial times in global temperatures, which in turn would have caused an increase of about 5 ppm of CO2 based on the scaling of CO2 change vs. temperature change from the last glacial maximum to preindustrial times.
4. I don’t know. Nobody that I’ve found has a good handle on the methane budget.
5. Climate models do not “assume” positive water vapor feedback, nor do they “assume” positive cloud feedback. Those are emergent properties of the models. Climate models do track other independent variables, including water vapor, clouds, etc., but isolate the effect from CO2 (and aerosols), different realizations of the natural variability are averaged together. Your last two sentences make no sense to me.
6. Saying that CO2 doesn’t track emissions is like saying that global temperature doesn’t track emissions. The statements are both true and false, depending on the time scale being examined. Both CO2 and temperature are subject to short-term natural variations, and natural variations of temperature and opacity drive natural variations in CO2 emissions and uptake. Since natural variations and uptake are variable and anthropogenic emissions are cumulative, the changes in total concentration from decade to decade are mostly anthropogenic. Natural variability of temperature is relatively large (compared to the anthropogenic component), and it takes multiple decades (or more, depending on volcanic activity) for the forced signal to emerge. You would likely dispute the claim that the accumulation of CO2 in the atmosphere is almost entirely anthropogenic in cause, but my point here is that the dominance of natural processes in year-to-year variations in concentration change does not contradict that assertion and is compatible with it.
– John
P.S. How can you in good conscience rely on a study such as Frolicher et al that relies upon those completely unreliable climate models? Or do you evaluate studies based on their results rather than their methods? Or, in this instance, on what you had preferred their results to be? 😉

@John N-G
Actually, Table 5 of Cook et al. shows that the authors rated their papers very differently than the interviewees did (p<0.001). Unfortunately, the sample of doubly-rated papers is not-representative (p<0.001), so we cannot conclude either way.

Richard –
Table 5 shows that, as one would expect, the authors are able to provide a more comprehensive evaluation while the abstracts are more ambiguous.
True, the populations of papers and papers self-rated by authors are different, but we can control for that difference. If we take the worst-case scenario and assume that the papers the authors self-rate as “reject AGW” all come from the most undersampled category of papers (those rated as ambiguous), the maximum possible adjusted “reject AGW” rate changes from 1.8% to 1.8% * (66.4% / 62.5%) = 1.9%. This is a distinction without a difference.
– John

Prof. Murry Salby’s presentation in Hamburg in April is a showcase of effective scientific communication based on mathematics. Salby gives strong evidence based on observation that the offset of concentration C(t) of atmospheric CO2 as a function of time t is determined by the offset of global temperature T(t) by an equation of the form

dC/dt = T for all t > 0, C(0) = 0,

after suitable scaling of C(t). In other words, C(t) is the integral of T(t), so that if T(t) = cos(t) then C(t) = sin(t) with a time lag of a quarter of a period.

The fact that in the equation dC/dt = T the concentration C(t) is determined by T(t), comes out as an aspect of stability (or wellposedness): Integration is a stable or well posed mathematical operation in the sense that small variations in the integrand T(t) gives small variations in the integral C(t).

On the other hand, differentiation is a an unstable or ill posed mathematical operation: small variations dC(t) in C(t) can give rise to large variations in dC(t)/dt as a result of division by a small dt. This means that viewing T(t) in the relation dC/dt = T to be determined by C(t) corresponds to an unstable mathematical operation.

To make a connection from cause to effect in physics, requires stability and thus in the observed relation dC/dt = T, it is C(t) which is determined by T(t) as the cause and not the other way around. Another way of expressing this fact is to say that C(t) lags T(t) with a quarter of a period, so that variations in the cause T(t) precedes the effect as variations C(t).

This is the observation from ice core proxies showing that temperature changes before CO2 and thus temperature is the dog and CO2 the tail with the dog wagging the tail, and not the other way around as the basic postulate of CO2 alarmism:

Thanks Dr. n-g for once again pulling the curtain back on the charlatans who populate this subject. It is obvious Cook has an agenda, and a conclusion before hand, and just went out to ask questions and research where the light was best to “prove” his preconceived notions. I find his poll question to be outrageous and an obvious planted question that reveals his motives, agenda, and his total lack of scientific objectivity and integrity.

Yes, though the public doesn’t know what CO2 equivalents are…but then again, they really do need to know. To calculate, you compare the radiative forcing per molecule and, in the case of emissions, adjust for atmospheric lifetime. – John N-G

You stated three points of contention (“problems” you have) with the “direct consequence of the burning of fossil fuels by humans” statement. I think those are a bit nitpicky as, in my opinion, they solely rest on the word “direct”:

While land use changes account for some of the warming due to carbon transferred from the soil and plant reservoirs to the atmosphere, the changes were strongly facilitated by FF use (via population increase and associated changes in farmland needs and how farmland is farmed, aside from the actual space we humans need, i.e. cities etc.), so is at least indirectly related to FF use.
Increases in all the GHGs you listed are directly caused by FF use: methane due to industrial waste management and increased meat consumption of an ever growing population, both caused by the industrial revolution, alongside direct emissions from FF mining and combustion; chlorofluorocarbons are produced from FF with FF energy; N2O increases due to increased fertilizer use, produced from the FF driven Haber Bosch process; tropospheric ozone increases due to FF combustion related hydrocarbon and NOx emissions. I think 2. is your weakest point.
Feedbacks are obviously also indirectly related to FF use. As for natural changes as drivers, I refer to http://www.skepticalscience.com/a-comprehensive-review-of-the-causes-of-global-warming.html, which suggests that only by referring to much longer time scales can you make that “problem” hold.